Service_Context.h

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00001 // -*- C++ -*-
00002 
00003 // ===================================================================
00004 /**
00005  *  @file   Service_Context.h
00006  *
00007  *  $Id: Service_Context.h 80861 2008-03-07 13:48:34Z johnnyw $
00008  *
00009  *  @author Balachandran Natarajan <bala@cs.wustl.edu>
00010  */
00011 // ===================================================================
00012 
00013 #ifndef TAO_SERVICE_CONTEXT_H
00014 #define TAO_SERVICE_CONTEXT_H
00015 
00016 #include /**/ "ace/pre.h"
00017 
00018 #include "tao/IOPC.h"
00019 
00020 #if !defined (ACE_LACKS_PRAGMA_ONCE)
00021 # pragma once
00022 #endif /* ACE_LACKS_PRAGMA_ONCE */
00023 
00024 TAO_BEGIN_VERSIONED_NAMESPACE_DECL
00025 
00026 namespace TAO
00027 {
00028   namespace CSD
00029   {
00030     class FW_Server_Request_Wrapper;
00031   }
00032 }
00033 
00034 /**
00035  * @class TAO_Service_Context
00036  *
00037  * @brief Helper class for managing the service context list
00038  *  information.
00039  *
00040  * This class is used to manipulate and access the service context
00041  * list that is passed around with every GIOP request/reply. The
00042  * definition of the service context list is simply a sequence of the
00043  * following structures:
00044  * typedef unsigned long ServiceId;
00045  * struct ServiceContext
00046  * {
00047  *   ServiceId          context_id;
00048  *   sequence <octet>   context_data;
00049  * };
00050  * typedef sequence <ServiceContext> ServiceContextList;
00051  *
00052  * the real motivation behind this class is to consolidate all the
00053  * marshalling and unmarshalling information pertaining to service
00054  * context list
00055  *
00056  * @note Somewhere down the line we may want to use this class for
00057  * fast access to the info that we need from the Service Context
00058  * List.
00059  */
00060 class TAO_Export TAO_Service_Context
00061 {
00062 public:
00063   /// Declare FW_Server_Request_Wrapper a friend
00064   /// This friendship makes the FW_Server_Request_Wrapper be able to
00065   /// clone the TAO_Service_Context data member in TAO_ServerRequest.
00066   friend class TAO::CSD::FW_Server_Request_Wrapper;
00067 
00068   /// Constructor
00069   TAO_Service_Context (void);
00070 
00071   /// = Generic components
00072 
00073   /// Insert the component into the list, making a copy of the octet
00074   /// sequence.
00075   void set_context (const IOP::ServiceContext &context);
00076 
00077   /// Insert the component into the list, making a copy of the octet
00078   /// sequence.  Search the list before insertion so that the
00079   /// insertion does not cause a duplicate context to be in the list.
00080   /// If the replace flag is true, update the specified context.
00081   /// Return 0 if the component was present and the replace flag
00082   /// was not set to true.
00083   int set_context (const IOP::ServiceContext &context, CORBA::Boolean replace);
00084 
00085   /// Insert the component into the list, but efficiently stealing the
00086   /// contents of the octet sequence.
00087   void set_context (IOP::ServiceContext &context);
00088 
00089   /// Get a copy of the context identified by <context.context_id>, return
00090   /// 0 if the component is not present.
00091   int get_context (IOP::ServiceContext &context) const;
00092 
00093   /// Get a reference to a context identified by id, return
00094   /// 0 if the component is not present.
00095   int get_context (IOP::ServiceId id, const IOP::ServiceContext **context) const;
00096 
00097   /// Get a copy of the Service Context corresponding to the given
00098   /// ServiceId.  The caller owns the returned Service Context.
00099   /**
00100    * @return 0 If a Service Context with the given ServiceId doesn't
00101    *           exist.
00102    */
00103   int get_context (IOP::ServiceId id, IOP::ServiceContext_out context);
00104 
00105   /// Set the context from the CDR stream and add that to the service
00106   /// Context list
00107   void set_context (IOP::ServiceId id, TAO_OutputCDR &cdr);
00108 
00109   /// Set the context from the CDR stream and return the context back
00110   /// to the caller. *Does not* modify the underlying service context
00111   /// list.
00112   void set_context (IOP::ServiceContext &context, TAO_OutputCDR &cdr);
00113 
00114   /// Is the @a id available in the underlying service context list? If
00115   /// so return true, else return false
00116   bool is_service_id (IOP::ServiceId id);
00117 
00118   /// = Marshaling and demarshaling the list
00119   int encode (TAO_OutputCDR& cdr) const;
00120   int decode (TAO_InputCDR& cdr);
00121 
00122   /// Return the underlying service context list
00123   IOP::ServiceContextList &service_info (void);
00124 
00125   /// @note This method is only for backward comptiblity. We
00126   /// need to get this removed once RT folks have their service
00127   /// addition info done through this interface
00128   const IOP::ServiceContextList &service_info (void) const;
00129 
00130 private:
00131   /// Helper methods to implement set_context()
00132   void set_context_i (const IOP::ServiceContext &context);
00133   void set_context_i (IOP::ServiceContext &context);
00134   void add_context_i (const IOP::ServiceContext &context);
00135   void add_context_i (IOP::ServiceContext &context);
00136   void set_context_i (IOP::ServiceId id, TAO_OutputCDR &cdr);
00137   void set_context_i (IOP::ServiceContext &context, TAO_OutputCDR &cdr);
00138 
00139   /// Helper methods to implement get_context()
00140   int get_context_i (IOP::ServiceContext &context) const;
00141 
00142   // Prevent copying
00143   TAO_Service_Context (const TAO_Service_Context &);
00144   TAO_Service_Context &operator= (const TAO_Service_Context &);
00145 
00146 private:
00147   /// The ServiceContextList info.
00148   IOP::ServiceContextList service_context_;
00149 };
00150 
00151 TAO_END_VERSIONED_NAMESPACE_DECL
00152 
00153 #if defined (__ACE_INLINE__)
00154 # include "tao/Service_Context.inl"
00155 #endif /* ! __ACE_INLINE__ */
00156 
00157 #include /**/ "ace/post.h"
00158 
00159 #endif  /* TAO_SERVICE_CONTEXT_H */

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